ACE model

The ACE model is a statistical model commonly used to analyze the results of twin and adoption studies. This classic behaviour genetic model aims to partition the phenotypic variance into three categories: additive genetic variance (A), common (or shared) environmental factors (C), and specific (or nonshared) environmental factors plus measurement error (E).[1] It is widely used in genetic epidemiology and behavioural genetics.[2][3] The basic ACE model relies on several assumptions, including the absence of assortative mating,[4] that there is no genetic dominance or epistasis,[5] that all genetic effects are additive, and the absence of gene-environment interactions.[3] In order to address these limitations, several variants of the ACE model have been developed, including an ACE-β model, which emphasizes the identification of causal effects,[3] and the ACDE model, which accounts for the effects of genetic dominance.[6]